Heat pipes have been suggested for cooling electronic components. Conventionally, a heat pipe comprises an evaporator to take in heat and a condenser to expel heat. Working fluid is contained in the heat pipe to transfer heat from the evaporator to the condenser. The heat entering the evaporator of the heat pipe boils the fluid and turns it into a vapor. The vapor expands in volume and travels to the condenser where it condenses to a liquid and gives up its heat. The liquid is then returned to the evaporator by gravity or a wick and starts the process again.
However, a heat pipe has its limits such as capillary pumping limit, nucleate boiling limit and entrainment limit. Measuring devices can measure heat transfer characteristics of the heat pipe which determine these limits. FIG. 4 shows a conventional measuring device 1 for measuring heat transfer characteristics of a heat pipe. The device 1 comprises a base 2 and a clamp 3. The clamp 3 defines a first hole 4 to receive the hot end or the cold end of the heat pipe, and a groove 6 communicating with the first hole 4. The groove 6 allows the heat pipe to be inserted into the first hole 4 freely. The base 2 defines a second hole 5 to receive a heating member which heats the hot end of the heat pipe, or to receive a cooling member which cools the cold end of the heat pipe. However, there is a clearance between the heat pipe and the inner surface of the clamp 3 due to machining error and so on. Air in the clearance unduly increases the thermal resistance. This may result in an error between measure values from the practical heat transfer characteristics of the heat pipe.
Thus, an improved measuring device for a heat pipe which can accurately measure heat transfer characteristics of the heat pipe is desired.